Jet entrainment control for a fluidic device

ABSTRACT

A fluidic device is provided with entrainment passages to the sides of the power stream supply nozzle which open up into the upper end of the interaction chamber. A control stream selectively directed into an entrainment passage in opposition to entrainment flow creates a low pressure zone between the power stream and the control stream causing the power stream to deflect towards that side of the interaction chamber. Maintenance of the power stream within a desired outlet passage may be achieved by feedback from that outlet passage to form the control stream.

United States Patent 3,270,960 9/1966 Phillips Donald A. Small Castine, Maine Apr. 3, 1969 Jan. 5, 1971 7 Coming Glass Works Corning, N.Y.

a corporation of New York Inventor Appl. No. Filed Patented Assignee JET ENTRAINMENT CONTROL FOR A FLUIDIC DEVICE 8 Claims, 6 Drawing Figs.

[1.8. CI. Int. Cl. Field of Search...

References Cited UNITED STATES PATENTS l37/8l.5 F15c 1/04 137/8 1 .5

3,417,770 12/1968 Denison l37/8l.5 3,420,253 H1969 Griffin 137/81.5 3,425,432 2/1969 Langley l37/81.5 3,467,122 9/1969 Jones l37/8l.5 3,468,326 9/1969 Cohen 137/8 1 .5 3,495,609 2/1970 Swartz 137/8 1 .5

Primary Examiner-Samuel Scott Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak ABSTRACT: A fluidic device is provided with entrainment passages to the sides of the power stream supply nozzle which open up into the upper end of the interaction chamber. A control stream selectively directed into an entrainment passage in opposition to entrainment flow creates a low pressure zone between the power stream and the control stream causing the power stream to deflect towards that side of the interaction chamber. Maintenance of the power stream within a desired outlet passage may be achieved by feedback from that outlet passage to form the control stream.

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SUPPLY INVENTOR DONALD A. SMALL ATTORNEYS .n-zr smnammsn'rconrnonronx rtumtc DEVICE BACKGROUND OF THE INVENTION LField ofthe Invention This invention relates to fluidic and/or flueric devices and 5 more particularly, to such devices which operate as either proportional or digital fluid amplifiers.

2. Description of thePrior Art a v Flueric and fluidic-devices employ various means for ensuring that the power stream, once it is positioned within a given "outlet or outputpassage, remains within this passage in the absence of an applied control signal. Some devices have attachment walls betweenthe outlet passages and the supply *nozzle for ensuring retention of 'the power stream along one.

side of the interaction chamber-for-discharge through a selected outlet passage. Further, in iorder to achieve disengagement of the power stream from one wall and reat- Lgtachment to the opposite wall of thelinteraction chamber, feedback passageshave been coupled to the outlet passages downstream of the-smlitter forming'the same, for feeding'a portion of the power stream backto theinteraction chamber and into momentum impact with the power stream downstream of the, supply nozzle to-cause controlled oscillation of the power stream from one outlet passage to the other.

summer 05' THE INVENTION This invention is dire cted to fluidic am nu'enc devices, such as fluid amplifiers in'either proportional or digital form, in

' w hich a powerstream passes through an interaction chamber j and discharges from the device'through outlet passages. Entrainment passagesare provided on eitherside of the supply nozzle and open up into the interaction chamber at its upstream end, whereby the moving power stream entrains flow from the passages and causes the same to be carried'along with the power stream. A control stream .isselectively fed into one of the entrainment passages in a direction opposite to that 1 of entrainment flow forcreating a zone of reducedpressure between the control stream and the power stream to pull the power stream laterally towards the interaction chamber wall stream. I

on the same side of the device as that of the applied control The control stream signal may be independently applied through a control passage alignedwi h the entrainment FIG. 6 is a plan view of the fluidic JR/NOR device of FIG. 5

.with control signals being applied simultaneously to the three control passages.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, there is shown in FIGS. 1 and 2, a fluidic amplifier l0 embodying the double jet entrainment control principle of the present invention For simplification purposes, the top cover or layer of the multiple laminate 'fluidic device 10 has been removed to show a configured intermediate layer or sheet 12 which overlies the imperforate bottom sheet .14 which forms a bottom cover for the device.

' downstream end of the chamber to formpower stream outlet passages26 and 28, respectively. This arrangement is conventional, and a power stream, indicated by arrows 30, moves through the interaction chamber 18 after exiting from supply nozzle 16 for discharge through outlet passages 28 and 30.

' Unlike the prior art amplifiers; there is further provided on "each sideof the supply nozzle entrainment passages 32 and 34, respectively, which are open at their upstream ends to the atmosphere. Thus, the atmosphere is entrained by the moving passage and may further comprise a feedback passage coupled v I to the outlet passage on the same side ofthe device. Separate control passages may be formed on either side of the interac- 'tion chamber with their axes at right angles to the entrainment and power stream flow andmay open up into the interaction power stream and flows in the manner of arrows 36 through the entrainment passages and out through outlet passages 26 and'28. I v A second important aspect of the present invention is the provision of control passages 38 and 40 having control ports and 44 opening up into the respective entrainment passages 32 and 34; in the vicinity of the interaction chamber 18. It is assumed that the amplifier 10 of FIGS. 1 and 2, which embodies the present invention, is a proportional amplifier, in

which case, the supply jet runs continuously so that the power stream passes (in the absence of applied control signals) in equal arnountsinto outlet passages 26 and 28. During this process, outside fluid is entrained, as indicated by arrows 36, through the openings and 48.

I Referring next to FIG. 2,if a fluid signal is applied to one of chamberadj acent the feedback passage discharge port. Alternatively, the control passages may open up along the interac- 1 tion chamber wall, downstream 'of the feedback passage discharge port into the entrainment passage. Afplurality of longitudinally spaced control ports may be provided within the entrainment passages upstream of the interaction chamber 7 signal applied to one-of the control ports.

. amplifier employing the double jet entrainment principles of a v the double jet entrainment principles-of i and the feedback passage discharge port to form a OR/NOR device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a fluidic amplifier employing the v double jet entrainment principles of the present invention I f operating in the absence of a control signal.

a control FIG. 2 is a plan view of the device of FIG. l-with FIG. 5 is a plan view of a secondembodirnent of a fluidic the present invention, operating in the-absence of a control signal. 1 FIG. 4 is a plan view of the fluidic device of FIG. 3 with a control signal appliedto theleft-hand control port. I 1

FIG. 5 is a planview of a fluidic OR/NQR- device employing the present invention,

in the absence of a control signal.

the control ports, such as control'p'o'rt 40, the entrained'flow from port 48 of entrainmentpassage 34 is limited due to the reverse flow of a control stream 50 exiting from control port 44 and opposing the flow indicated by arrow 36 within passage 34. This establishes a low pressure region A between the power stream or supply jet 30 and the control stream 50 exiting through control port 44. Since essentially atmospheric pressure exists on the other side of the power stream 30, the power stream is bent towards outlet passage 28 and a much larger output signal is available in outlet passage 28 than in outlet passage 26. The difference between the output signal in plied to control passages 40 and 38. Therefore, by definition,

the fluidic device 10 has a gain greater than one. The value of gain is dependent upon the details of the design, the splitter distance, nozzle shapes and location, exhaust areas, vents, aspect ratio, etc. The control nozzles'of ports 42 and 44 and the entrainment passages, which therefore, form exhaust areas, may be reversed so that the control streams or jets are parallel to and in the same direction as the supply or power stream 30. Further, instead of the control ports opening up with their axes in line with the axis of the power stream nozzle, theymay be at some inclination with respect to the supply jet to take advantage of momentum exchange. Also, as indicated in FIGS. 1 and 2, vents 52 may be provided in the outlet passages 26 and 28 to provide stability under load, or alternatively, a center dump vent (not shown) may also be used to provide stability.

The double-jet entrainment principles may also be applied to a digital element by incorporating feedback loops in the outlet passages. Reference to FIGS. 3 and 4 show a digital fluid amplifier forming a second embodiment of the present invention. The fluidic device 110 is formed in similar manner to that of the amplifier in FIGS. 1 and 2. An intermediate configured sheet overlies a bottom sheet 114 and a cover (not shown) overlies sheet 112 to form sealed passages, with the exception of the fluid openings at the sides of the device. Thus, a supply nozzle 116 discharges a power stream 130 into the interaction chamber 118 and against a splitter 124 at the downstream end thereof. The splitter acts in conjunction with the curved sidewalls 120 and 122 to define outlet passages 126 and 128, respectively. In like manner to the previous embodiment, entrainment passages 132 and 134 are formed on either side of nozzle 116 and have openings 146 and 148 within sidewall thereof, whereby the atmosphere is entrained by the movement of power stream 130 as it passes through the interaction chamber 118. In such devices, due to lack of symmetry, the power stream tends to attach itself to one of the walls, for instance, wall 120, such that most of the power stream moves into the outlet passage 126 in the absence of an applied control signal. However, some of this flow is diverted into a feedback passage 138 which is similar to the control passage 38 of the proportional device. This diverted flow, indicated by arrow 160, moves into the entrainment passage 132 in an opposite direction to the entrainment flow 136. This creates a low pressure zone A between the power stream or supply jet 130 and the feedback signal 160 which holds the power stream in the outlet passage 126 in identical fashion to the applied control signal in the previous embodiment.

The device, of course, includes a second feedback passage 140, which extends from the outlet passage 128 to the entrainment passage 134, with the feedback passage discharge port 144 having its axis in line with the entrainment passage 134.

In addition to the feedback passages, there is also provided applied control signal passages in the manner of conventional fluid amplifiers. These passages 162 and 164 have their respective control ports 166 and 168 opening up into the entrainment passage just upstream of the feedback passage discharge ports 142 and 144. Further, the digital fluidic element is provided with alternate control passages 170 and 172 having control ports 174 and 176 opening up onto the attachment walls 120 and 122, downstream of the control ports 166 and 168. The control passages 170 and 172 operate similarly to passages 162 and 164 and may be used alternatively as desired.

In either case, the operation of the device may be seen by reference to FIGS. 3 and 4 wherein a control signal is applied to one control passage, such as passage 162, as indicated by arrow 178. The feedback jet 160 is now deflected toward the power jet 130 and the low pre$ure region A existing between the supply jet and the feedback jet is destroyed. The supply jet in turn will be deflected towards the outlet passage 128 from outlet passage 126. The initially described feedback loop is destroyed, and a new feedback loop illustrated by arrows 160' is created within feedback passage 140, FIG. 4. This results in the power stream or supplyjet remaining in outlet passage 128 even after the control signal 178 ceases within control passage 162. Thus, the device 110 constitutes a flip-flop, since a large signal 130 is controlled by a smaller signal 178 and after the signal 178 ceases, the output remains unchanged. The location of the control nozzles 170 and 172 is merely indicative of the face that the control nozzles may be placed at various alternate locations. However, with respect to control nozzles 170 and 172, they operate simply as a result of an increase in pressure on the active control side of the supply jet or power stream 130 to force it from its present outlet passage to the other outlet passage. Some momentum effect may be present.

The digital amplifier of FIGS. 3 and 4i'i'ia be modified to perform specific logic functions,.such.as that of a multi input OR/NOR gate. Reference to FIGS. 5 and 6 shows an OR/NOR device at 210 employing an outer i'rhperforate cover (not shown), an intermediate configured sheet 212 and a bottom imperforate sheet 214 which acts asth bottom cover. Again, a supply nozzle 216 supplies a p'ofwer stream 230 or supply jet, which, due to chamber configuration, normally flows through the interaction chamber 218 towardsplitter 224 and into the NOR outlet passage 226 rather th'a'rre'ifiting through OR outlet passage 228. In similar fashion, entrainment passages 232 and 234 are formed on either side of the supply nozzles. A feedback loop is formed by passage 238 in which a portion 260 of the power stream is diverted to form a feedback jet exiting through feedback passage discharge port 242 and into the entrainment passage 232, in-a direction opposite to that of entrainment flow 236 entering from passage opening 246. Rather than a single control passage to one side of the entrainment passage and/or interaction chamber, the device of FIGS. 5 and 6 employs a series of longitudinally spaced passages 262, 272 and 282 having respective control ports 266, 276 and 286 opening onto entrainment passage sidewall 284 at spaced longitudinal locations. In the absence of an OR control signal at one of the passages, flow continues from the power stream nozzle 216 to the NOR outlet passage 226. However, upon the receipt of a fluid signal in any one or all of the gates or passages 262, 272 or 282, deflection of the feedback jet 260 occurs toward the power jet 230 to cause the power stream to flip from NOR outlefpassage 226 to OR outlet passage 228. However, in this case, as soon as the control signal is removed, the supply jet returns to the original NOR outlet passage due to the fact that left-hand NOR passage 226 is the only passage which carries a feedback loop to ensure creation of a low pressure region A between power stream 230 and feedback jet 26 0. The OR gate operation is seen by reference to FIG. 6 in which signals are applied simultaneously to gates 262, 272 and 282 to cause momentary deflection. The device of FIGS. 5 and 6 operates as an OR OR/NOR. device, since the feedback loop is in the NOR outlet passage 226, whereby a signal applied at any one of the gates 262, 272,

282 causes power stream movement from the NOR passage.

Biasing can be accomplished in any of several ways. One alternative is to simply aim the power stream or supply jet at the stable (NOR) outlet passage in which case, there are no feedback passages for either outlet passage. The more positive arrangement is the one shown in FIGS. 5 and 6, in which the feedback loop for the NOR outlet passage is provided with the proportional control nozzles on that side of the device,

without a feedback loop being connected to theother passage. V

The devices illustrated were formed, in actual use, from Plexiglas. With respect to the embodiment of FIG. 1, the nozzle widths were 0.030 inch and aspect ratios of l, 2 and 3 were timed. For an aspect ratio of 3, the flow gain varied between 1 and 2, and the pressure gain varied between 2 and 3. For an aspect ratio of 2, the flow gain varied between 2 and 3, as did the pressure gain. For an aspect ratio of l, the flow gain was about 2 to 3 and the pressure gain was about 1. These gains are simply representative of the gains to be expected employing the principles of the present invention in such fluidic devices. A flip-flop was made by attaching feedback loops to a proportional device. The loops were made of Tygon tubing and the minimum supply pressure for operation was about 3 inches of water and the minimum control pressure necessary H to switch was about one-tenth of the recovery pressure. The

recovery pressure was about 25 percent of the supply pres sure. While these devices operated satisfactorily, it was apparent that improved efficiency may be achieved employing more sophisticated models. v,

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in the form and detailed may be made therein without departing from the spirit and scope of the invention.

chamber therefrom and in line therewith, at least one entrainment passage fluid coupled to the interaction chamber to one side of the power streaminlet nonle, at least one entrainment control passage in said device for directing an applied control stream into said entrainment passage in opposition to entrainment flow, whereby a low-pressure. zone is created between said power stream and said control stream to cause said power stream to move laterally toward said low-pressure zone.

2. The fluidic device as claimed in claim 1 further comprising vents coupled to said outlet passages for preventing pressure buildup in the outlet passages during power stream flow therethrough.

3. The fluidic device as claimed in claim 1 further comprising a plurality of control passages, each having a control port opening up into said entrainment passage at longitudinally spaced locations, whereby application of a control signal to any one of said control ports causes deflection of said power stream toward theoutlet passage on the opposite side of said interaction chamber from said series of control ports.

4. The fluidic device as claimed in claim 3 further including a feedback passage having one end fluid coupled to the outlet passage on the same side of said device as said series of control ports with said feedback passage discharge port having its axis generally aligned with the axis of said entrainment passage and positioned downstream thereof.

5. The fluidic device as claimed in claim 1 further comprising'means for directing a second control stream toward said power stream downstream of said supply nozzle to deflect the same regardless of the presence of said first control stream.

6. The fluidic device as claimed in claim 5 wherein said means for directing a second control stream towards said power stream comprises a control port to one side of said int'eraction chamber and downstream of said supply nozzle with its axis at right angles to said first control stream and said power stream and spaced laterally from said power stream.

7. A fluidic device as claimed in claim 5 wherein said means for directing a control stream into said entrainment passage comprises a feed back passage having one end fluid coupled to an associated power stream outlet passage and the other end opening up into said entrainment passage at the interaction chamber end thereof and laterally displaced to one side ofsaid power stream path.

8. The fluidic device as claimed in claim 7 further comprising an additional control passage opening up into said interaction chamber downstream of said feedback passage discharge port. 

1. A double-jet entrainment fluidic device comprising a supply nozzle for directing a power stream toward a plurality of power stream outlets on the opposite side of the interaction chamber therefrom and in line therewith, at least one entrainment passage fluid coupled to the interaction chamber to one side of the power stream inlet nozzle, at least one entrainment control passage in said device for directing an applied control stream into said entrainment passage in opposition to entrainment flow, whereby a low-pressure zone is created between said power stream and said control stream to cause said power stream to move laterally toward said low-pressure zone.
 2. The fluidic device as claimed in claim 1 further comprising vents coupled to said outlet passages for preventing pressure buildup in the outlet passages during power stream flow therethrough.
 3. The fluidic device as claimed in claim 1 further comprising a plurality of control passages, each having a control port opening up into said entrainment passage at longitudinally spaced locations, whereby application of a control signal to any one of said control ports causes deflection of said power stream toward the outlet passage on the opposite side of said interaction chamber from said series of control ports.
 4. The fluidic device as claimed in claim 3 further including a feedback passage having one end fluid coupled to the outlet passage on the same side of said device as said series of control ports with said feedback passage discharge port having its axis generally aligned with the axis of said entrainment passage and positioned downstream thereof.
 5. The fluidic device as claimed in claim 1 further comprising means for directing a second control stream toward said power stream downstream of said supply nozzle to deflect the same regardless of the presence of said first control stream.
 6. The fluidic device as claimed in claim 5 wherein said means for directing a second control stream towards said power stream comprises a control port to one side of said interaction chamber and downstream of said supply nozzle with its axis at right angles to said first control stream and said power stream and spaced laterally from said power stream.
 7. A fluidic device as claimed in claim 5 wherein said means for directing a control stream into said entrainment passage comprises a feed back passage having one end fluid coupled to an associated power stream outlet passage and the other end opening up into said entrainment passage at the interaction chamber end thereof and laterally displaced to one side of said power stream path.
 8. The fluidic device as claimed in claim 7 further comprising an additional control passage opening up into said interaction chamber downstream of said feedback passage discharge port. 